Faecal parasites increased and fish sauce spread tapeworm during rule of Roman empire

Roman sanitation systems left people suffering from whipworm, roundworm, dysentery and intestinal parasites, according to archaeologists who say hygienic innovations such as multi-seat toilets and heated public baths only improved the smell of their users in Britain 2,000 years ago.

Evidence from fossilised faeces, lice combs, ancient latrines, human burials and textiles show that newly-introduced washing facilities, sewerage systems and piped aqueduct water failed to halt a rise in diseases caused by parasites.

Despite a lauded culture of regular bathing, Romans were as prone to mites and fleas as Viking and medieval populations, and delousing would have been a daily routine for many.

“Clearly, not all Roman baths were as clean as they might have been,” says Dr Piers Mitchell, a parasite infection specialist at the University of Cambridge who carried out the investigation.

“The widespread nature of both intestinal parasites and ectoparasites such as lice also suggests that Roman public baths surprisingly gave no clear health benefit either.

“Modern research has shown that toilets, clean drinking water and removing faeces from the streets all decrease risk of infectious disease and parasites.

“So we might expect the prevalence of faecal oral parasites such as whipworm and roundworm to drop in Roman times – yet we find a gradual increase.

“This latest research on the prevalence of ancient parasites suggests that Roman toilets, sewers and sanitation laws had no clear benefit to public health.

“It seems likely that while Roman sanitation may not have made people any healthier, they would probably have smelt better.”

Warm water used in the communal bathhouses could have reversed their intended effect, helping spread parasitic worms in baths where scum would build from human dirt, cosmetics and infrequent water changes.

Despite implementing new refuse laws, the Romans also used human excrement on crops – a tactic which could have resulted in the spread of parasite eggs unless the faeces were composted for “many months”.

“It is possible that sanitation laws requiring the removal of faeces from the streets actually led to re-infection of the population,” says Dr Mitchell.

“The waste was often used to fertilise crops planted in farms surrounding the towns.”

A popular sauce made of fish, herbs, salt and flavourings, known as garum and used as a kitchen ingredient and medicine, could have acted as a “vector”.

“The manufacture of fish sauce and its trade across the empire in sealed jars would have allowed the spread of the fish tapeworm parasite from endemic areas of northern Europe to all people across the empire,” believes Dr Mitchell, who says the sauce was fermented in the sun rather than cooked.

“This appears to be a good example of the negative health consequences of conquering an empire.”

One Roman doctor, Galen, is said to have described intestinal roundworm, pinworm and a species of tapeworm during the 2nd century.

He theorised that the parasites were spontaneously generated in putrefied matter under the effect of heat, and recommended diet changes, bloodletting, and cooling and drying medicines as remedies to restore the “four humours” of black bile, yellow bile, blood and phlegm.

• Read the full report, Human parasites in the Roman World: health consequences of conquering an empire.

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Three places to find out about toilets in

Abbey Pumping Station, Leicester
The current exhibition, Flushed with Pride, tags a history of everyday terminology for our bodily waste on a toilet door in graffiti. There is a talking toilet (in a modern bathroom setting), Victorian toilets and Roman water pipes, a working water pump powered by a paraffin engine and a unique interactive toilet with a see-through bowel and cistern, where the journey of an object can be followed from flush to drain.

Science Museum, London
How does a toilet work? Find out in one of the interactive exhibits in current exhibition The Secret Life of the Home.

Museum of Science and Industry, Manchester
Visit the Underground Manchester Gallery to find out why clean water and effective sewerage were vital to public health and Manchester's development. Located in the cellars of the Station Building, this gallery tells the story of Manchester's water supply and sanitation from Roman times to the present day.